Manufacture of artificial silk



Patented Aug. 1141, i923.

EMILE BRONNERT, OF MULH AUS EN, FRANCE.

MANUFACTURE OF ARTIFICIAL SILK.

No Drawing.

To all whom it may concern Be it known that I, EMILE BRONNERT, a citizen of the Republic of France, residing in Mulhausen, Alsace-Lorraine, France, have invented certain new and useful Improvements in the Manufacture of Artificial Silk, of which the following is a specification.

The stretch-spinning of filaments formed from aqueous cellulose solutions from wide apertures is already known, and has been used especially for cuprammonia cellulose solutions in such a manner that from the very beginning the cellulose solutions used contained a high percentage of only slightly degraded cellulose and were therefore of great consistency. Such processes are disclosed in U. S. Patents Nos. 710,819 and 957,460. In the interest of easy spinning work, comparatively wide nozzle apertures,

0 i. e, apertures of 0.84.00 IIHTL, which are less subject to choking, were used, and finally the solutions'were allowed, under only slight pressure, to fall down through quiescent liquids which remained in suspension under atmospheric pressure, the solvent (ammonia) being withdrawn from the thread by said liquid consisting essentially of water.

The coppercellulose is the primary insoluble ingredient of the cuprammonia cellulose solution. This insoluble ingredient may render it possible for the spinning to be effected direct in water, although cuprammonia'cellulose solution with water can be 3: diluted to form a clear solution. The ammonia is rapidly eliminated from the threads and leaves the insoluble copper cellulose threads behind it.

With viscose the conditions are quite different; for if in the spinning of young and normal ripened viscose the soda lye removed from the jet by a spinning bath containing water only, soda cellulose Xanthogenate theoretically remains, which is very easily soluble in water. Weak mineral acid likewise will not suffice to produce insoluble threads even with young viscose that is very poor in alkali, because the alkali cannot be removed with sufiicient rapidity to enable an insoluble xanthogenate or the like to be left behind.

If however on the other hand a stronger acid is used, then under these working conditions any stretching of the thread is out of question, for then, under the influence of Application filed September 13, 1920. Serial No. 409,975.

the acid, decomposition into hydrate takes place too rapidly to enable the stretching and spinning process to be carried out.

In the spinning of old viscose of relatively high ripeness on the contrary, a cellulose hydrate very quickly forms that is not soluble in water, and coagulated immediately if it enters water, because it consists of a xanthogenate containing but few xanthogenate radicals and little bound sodium, and because it becomes fully insoluble if the last traces of sodium are removed from it.

F or this reason there would have been an apparent possibility of the stretch-spinning process being carried out with viscose of a high degree of ripeness, but in practice a viscose of this kind cannot be worked.

Now it has been found that the stretchspinning operation can nevertheless be carried out with ordinary viscose, and even with comparatively young Viscose, if only small quantities, for example 0.5 to 1 per cent, of the hereinafter mentioned acids are contained in the spinningmedium, and if care is taken that the quantity of the other chemicals in the spinning medium just suffices for the salting out of the cellulose Xanthogenate in a state still able to be stretched out.

According to the present invention it has been found that viscose which contains 10 to 12 per cent of only very slightly degraded cellulose, (preferably cotton cellulose,) and 8 to 10 per cent of caustic soda, and which is consequently of rather a thick consistency, can be stretched and drawn out into a thread of about 11} to 2 deniers at a speed of about 30 to 40 meters'per second, ifvit is allowed to sink down through a suitable spinning funnel such as for example the kind de- 0 scribed in the specification of U. S. Patent No. 750,502, containing a suitable medium for coagulatingthe viscose jet. The following coagulating solutionhas been found to give excellent results Benzene monosulphonic acid,

or a raw mixture of monosulphonic and disulphonic acids 1 gramme Ammonium sulphate 5 grammes Glucose 10 grammes Water 100 grammes threads drawn out of the funnel are received on a reel and washed with 2 per cent sulphuric acid or fixed in some other known way and dried, preferably under tension.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is 2-- 1. A process for the manufacture of fine viscose silk threads by employing the stretch-spinnin process, comprising issuing ,viscose of re atively thick consistency through relatively wide apertures into a coagulating solution containing a soluble aromatic sulpho-acid, an ammonium salt and glucose.

viscose silk threads by employing the stretch-spinning process, comprising issuing viscose containing a hi h percentage of only slightly degraded cel ulose through apertures of 0.8 to 1.00 mm. into a solution containing from 0.5 to 1% of a soluble sulphoacid, about 5% of an ammonium'salt and 510% of glucose.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

EMILE B-RONNERT.

Witnesses: V

L. R. Ln SALIS, N. L. MUMBORGER. 

